Blogs

Events

Stories

Attention: RHN Hosted will reach the end of its service life on July 31, 2017.
Customers will be required to migrate existing systems to Red Hat Subscription Management prior to this date.
Learn more here

Details

Updated ruby packages that fix two security issues are now available forRed Hat Enterprise Linux 4 and 5.

The Red Hat Security Response Team has rated this update as having moderatesecurity impact. Common Vulnerability Scoring System (CVSS) base scores,which give detailed severity ratings, are available for each vulnerabilityfrom the CVE links in the References section.

Ruby is an extensible, interpreted, object-oriented, scripting language. Ithas features to process text files and to do system management tasks.

A denial of service flaw was found in the implementation of associativearrays (hashes) in Ruby. An attacker able to supply a large number ofinputs to a Ruby application (such as HTTP POST request parameters sent toa web application) that are used as keys when inserting data into an arraycould trigger multiple hash function collisions, making array operationstake an excessive amount of CPU time. To mitigate this issue, randomizationhas been added to the hash function to reduce the chance of an attackersuccessfully causing intentional collisions. (CVE-2011-4815)

It was found that Ruby did not reinitialize the PRNG (pseudorandom numbergenerator) after forking a child process. This could eventually lead to thePRNG returning the same result twice. An attacker keeping track of thevalues returned by one child process could use this flaw to predict thevalues the PRNG would return in other child processes (as long as theparent process persisted). (CVE-2011-3009)

Red Hat would like to thank oCERT for reporting CVE-2011-4815. oCERTacknowledges Julian Wälde and Alexander Klink as the original reporters ofCVE-2011-4815.

All users of ruby are advised to upgrade to these updated packages, whichcontain backported patches to resolve these issues.

Solution

Before applying this update, make sure all previously-released erratarelevant to your system have been applied.